Surge-actuator for brake system

ABSTRACT

A surge type brake actuator for actuating hydraulically actuated brakes on a towed vehicle and including apparatus for providing a force multiplication whereby an increased fluid pressure output can be obtained particularly for disk brake actuation. The force multiplication apparatus includes a toggle linkage system and a cam that actuates the joint of the toggle linkage. Furthermore, a shock absorber is interposed in the apparatus for providing a smoother brake operation.

United States Patent [1 1 Kolm Mar. 12, 1 974 [54] SURGE-ACTUATOR FORBRAKE SYSTEM 2,916,107 12/1959 Huentelman 188/112 [75] e Inventor:Richard H. Kolm, Waukesha, Wis.

I Primary ExaminerDuane A. Reger [73] Asslgnee: rx ls Company, RomulusAttorney, Agent, or Firm-Harness, Dickey & Pierce [22] Filed: Mar. 16,1972 e 57 ABSTRACT PP bio-12351337 A surge type brake actuator foractuating hydrauli- I cally actuated brakes on a towed vehicle andincluding [52] CL 188/112 apparatus for providing a force multiplicationwhereby [51] m C. ""'11"""1'111...11....11 m 7/20 en ieeeeeeee fluid beeeeeieee [58] Field 188/112 142 particularly for disk brake actuation.The force multiplication apparatus includes a toggle linkage system 56]References Cited and a cam that actuates the joint of the togglelinkage.

Furthermore, a shock absorber is interposed in the ap- UNITED STATESPATENTS paratus for providing a smoother brake operation. 2,354,2687/1944 McNamara 188/112 2.642961 e 6/l953 Teal....; 188/112 5 Claims, 5Drawing Figures ll l h L If I III ar lwuHll llu wlp PATENTEU 12 B74SHEET 1 OF 2 SURGE-ACTUATOR FOR BRAKE SYSTEM SUMMARY BACKGROUND OF THEINVENTION The present invention relates to surge type brake actuatorsfor actuating hydraulic brakes on a towed vehicle.

For towed vehicles, such as trailers, it is common to provide a selfcontained hydraulic brake system which operates independently of thebrake system on the towing vehicle. This has been accomplished by use ofa surge actuator which is built into the tongue of the towed vehicle ina manner such that when the towing vehicle is braked, the resultantforce on the tongue will be utilized to create a fluid pressure used toactuate the trailer brakes. There are practical limitations on themaximum fluid pressure attainable with conventional surge actuators.This factor becomes especially significant when the actuator is usedwith disk brakes. In the present invention this problem is solved byutilizing an actuating structure in the surge actuator which provides adesired force multiplication. In addition, in the present invention therate of application of fluid pressure can be selectively varied over therange of expected tongue loads to optimize braking effect.

Therefore, it is an object to provide a novel surge actuator providingfor increased output fluid pressure in response to nonnal braking forceson the actuator.

It is another object of the present invention to provide a novel surgeactuator utilizing force multiplying structure.

It is still another object of the present invention to provide a novelsurge actuator for use with disk brakes.

It is another object of the present invention to provide a novel surgeactuator in which the response to input force can be selectively variedto optimize braking.

Other objects, features, and advantages of the present invention willbecome apparent from the subsequent description and the appended claims,taken in conjunction with the accompanying drawings, in which: 1

FIG. I is a pictorial view of an assembly of a tractor and trailer withthe trailer including a surge actuator embodying features of the presentinvention;

FIG. 2 is an enlarged side elevational view of the surge actuator ofFIG. 1;

FIG. 3 is a top elevational view of the apparatus of FIG. 2; and

FIGS. 4 and 5 are sectional views taken along the lines 4-4 and 55 inFIG. 3.

Looking now to FIG. 1 a tractor 10 is shown towing a trailer 12 via aconventional hitch located in a tongue assembly 14, which assembly 14includes a surge actuator assembly 16 embodying features of the presentinvention. The surge actuator assembly 16 has a hydraulic outlet line 18connected to an actuating cylinder for a disk brake assembly 20connected with a wheel assembly 22. When the tractor 10 is braked theforce on the surge actuator assembly 16, via the tongue assembly 14, isutilized to provide a hydraulic fluid pressure output to energize thedisk brakes 20.

The surge actuator assembly 16 includes a telescoping housing assembly24 connected intermediate the ends of the tongue assembly 14 and has anouter member 26 connected to one portion and an inner member 28connected to another portion of tongue assembly 14.

The outer member 26 is provided with a transverse tube 30 which isadapted to receive a pin whereby the outer member 26 can be secured tothe tongue assembly 14. The inner member 28 can be connected to assembly14 via a flange 32.

Looking now to FIGS. 2-5, the outer member 26 has a master cylinder (andreservoir) assembly 34 mounted thereon (via bolts 35) with fluid line 18connected to the outlet thereof. The master cylinder assembly 34 can beof a conventional construction which is actuated to provide a fluidpressure output in response to the force applied to an actuating plunger36. The plunger 36 is connected to and actuated by a linkage 38 and cam40.

The linkage 38 includes a first pair of arms 42 pivotally connected atone end to a yoke 44 which is secured to actuating plunger 36. A roller46 is located between arms 42 and roller 46 and arms 42 are pivotallysupported on yoke 44 via a pin 48.

The arms 42 are pivotally connected at their opposite ends to one end ofa second pair of arms 50 which are located outboard of arms 42. A secondroller 52 is supported between arms 42 and roller 52, arms 50, and arms42 are all pivotally or rotatably connected together via a pin 54. Theopposite ends of arms 50 are pivotally connected to the forward end ofthe outer housing 26 via a stationary pin 56. A bushing 58 spaces theopposite ends of arms 50 the proper amount to maintain parallelism.

The outer and inner members 26 and 28, respectively, are of generallyrectangular tubular construction with the inner member 28 slidablysupported within the forward end of the outer member 26. The innermember 28 is slidably supported on a plurality of wear pads 60 and awear plate 62, all of which have good bearing and wear characteristics.The inner member 28 has slots 64 on opposite sides, which slots receivethe pin 56. Thus in the fully separated position of outer and innermembers 26, 28 the slots 64 engage the pin 56 and hold members 26, 28together whereby the pulling force in towing the trailer 12 will betaken by the pin 56. During braking of the tractor 10, however, theinner member 28 will slide inwardly into outer member 26, as permittedby slots 64. A cam plate structure 66 is fixed to one interior side ofthe inner member 28 such as to be located proximate the interconnectionof arms 42 and S0. The structure 66 is generally T-shaped in crosssection and includes a flat base 68 and a flat leg member 70. The legmember 70 (and end of base 68) is provided with an inclined, cam surface72 which is normally located in confrontation with the roller 52. Thusas the inner member 28 telescopes into the outer member 26 duringbraking, the cam surface 72 engages roller 52 to actuate the linkageassembly 38. A wear plate 73 is located on the interior, confrontingside of inner member 28 such as to provide a good wear surface forroller 46. The linkage assembly 38 provides a toggling action which incombination with the inclined cam and roller effect of cam surface 72and roller 52 will provide for a substantial, determinable mechanicaladvantage which, inresponse to the input force on tongue assembly 14,provides a resultant increased the necessary pressure capability for thedisk brake assembly 20.

A shock absorber 74 has one end connected to outer member 26 and theother end to inner member 28 and acts to dampen the effect of suddensharp loads on the tongue assembly 14 and hence helps to provide forsmoother braking effect.

Note that the cam surface 72 can be made to a variety of contours andhence can be readily constructed in a manner to provide a desiredbraking effect.

Thus the surge actuator of the present invention not only provides aconstruction for maximizing the utilization of the force available atthe tongue of the trailer but also provides a structure which lendsitself to optimized braking via cam surface selection.

While it will be apparent that the preferred embodiments of theinvention disclosed are well calculated to fulfill the objects abovestated, it will be appreciated that the invention is susceptible tomodification, variation and change without departing from the properscope or fair meaning of the invention.

Whatis claimed is:

1. In a vehicle adapted to be towed by a towing vehicle with the towedvehicle having hydraulically actuated brakes actuated by a systemindependent of the brake system of the towing vehicle and with the towedvehicle having a tongue assembly adapted to be connected to the towingvehicle the improvement comprising: surge actuator means mounted in thetongue assembly and actuable in response to a compressive force on thetongue assembly for actuating the towed vehicle brakes, said surgeactuator means comprising a pair of housing members, connecting meansfor connecting said pair of housing members for limited relativemovement therebetween, a master cylinder assembly supported on one ofsaid housing members and connected to the towed vehicle, brake systemfor providing fluid pressure thereto with the magnitude of fluidpressure varying in accordance with the magnitude of an input force, apair of linkage members connected together at one end in a togglearrangement, the opposite end of one of said linkage members connectedto one of said housing members, the opposite end of the other of saidlinkage members connected to said master cylinder assembly for providingsaid input force, and actuating means connected to said housing memberand to said linkage members for actuating said linkage members toprovide said input force as an increased multiple of the compressiveforce.

2. The apparatus of claim 1 with said actuating means comprising a cammember and a roller.

3. The apparatus of claim 2 with said cam member being connected to oneof said housing members and with said linkage members being connected tothe other one of said housing members, said roller being rotatablysecured at the connection between said pair of linkage-members.

4. The apparatus of claim 3 including another roller member rotatablyconnected to said opposite end of said other of said linkage member, andmeans pivotably supporting said opposite end of said one linkage memberto said other one of said housing members.

5 The apparatus'of claim 4 further comprising shock absorber meansconnected between said housing members for dampening the relative motiontherebetween.

1. In a vehicle adapted to be towed by a towing vehicle with the towedvehicle having hydraulically actuated brakes actuated by a systemindependent of the brake system of the towing vehicle and with the towedvehicle having a tongue assembly adapted to be connected to the towingvehicle the improvement comprising: surge actuator means mounted in thetongue assembly and actuable in response to a compressive force on thetongue assembly for actuating the towed vehicle brakes, said surgeactuator means comprising a pair of housing members, connecting meansfor connecting said pair of housing members for limited relativemovement therebetween, a master cylinder assembly supported on one ofsaid housing members and connected to the towed vehicle brake system forproviding fluid pressure thereto with the magnitude of fluid pressurevarying in accordance with the magnitude of an input force, a pair oflinkage members connected together at one end in a toggle arrangement,the opposite end of one of said linkage members connected to one of saidhousing members, the opposite end of the other of said linkage membersconnected to said master cylinder assembly for providing said inputforce, and actuating means connected to said housing member and to saidlinkage members for actuating said linkage members to provide said inputforce as an increased multiple of the compressive force.
 2. Theapparatus of claim 1 with said actuating means comprising a cam memberand a roller.
 3. The apparatus of claim 2 with said cam member beingconnected to one of said housing members and with said linkage membersbeing connected to the other one of said housing members, said rollerbeing rotatably secured at the connection between said pair of linkagemembers.
 4. The apparatus of claim 3 including another roller memberrotatably connected to said opposite end of said other of said linkagemember, and means pivotably supporting said opposite end of said onelinkage member to said other one of said housing members.
 5. Theapparatus of claim 4 further comprising shock absorber means connectedbetween said housing members for dampening the relative motiontherebetween.